Peatlands are important ecosystems that are responsible for a large portion of greenhouse gas emissions, including methane and carbon dioxide. With ongoing global climate change, it is unknown to what degree peatlands will turn from carbon sink to source as large amounts of organic matter become exposed to the atmosphere. Many studies have shown that organic matter reduction, a process where microbes use redox-active organic matter as electron acceptors, is an overlooked but important control on methane production, as it is a more thermodynamically favorable process than methanogenesis. To understand how organic matter reduction is affected by fluctuations in the water table, a common substrate was deployed at different depths in a fen undergoing water table manipulation at the Alaskan Peatland Experiment. We deployed substrates using peat peepers which allowed for the substrate to be exposed to the environmental conditions of each manipulation. Using an electron shuttling assay, we saw that the substrate had the lowest amount of organic matter reduction in the lower water table treatment compared to the control and raised treatment. Most importantly, these results showed that using peat peepers and a common substrate allows us to track possible changes in organic matter reduction at the site. This has exciting implications for studying the connections between redox dynamics and methane production in situ as ecosystems continue to adapt to global climate change.
Ecology & Evolutionary Biology Graduate Student, CU Boulder